Repeat rocker arm failure 04 MY engine, update rocker arm and carrier.

lmorris · November 2, 2015

My now retired counterpart replaced a pushrod and updated rocker arm earlier. Now it's back with the same rocker arm off. #2 intake. Only things visibly wrong are the hold down bolt is broken and the tops of the valve stems are worn. Plus the valve bridge is very sloppy on the valve stems, which doesn't seem normal either. Pushrod and rocker arm both look good. The recess for the pivot ball on both rocker arm and carrier are both good. For the life of me I can't remember if the newer style rockers had the bolt spacer on them. Searched pictures show no bolt spacer, but for some reason I am thinking there is one. This had no spacer. My initial thought is that the valve stem wear was missed and the bridge moving around is the cause here. Any thoughts. BTW this is my Service manager's kid's truck......No pressure right?

Edit: the rocker arm mushroom thingy that pushes on the valve bridge is also missing. I am now thinking the worn valve stems were missed last time. And the resulting movement of the bridge dislodged the end of the rocker and thus resulted in the arm falling off the carrier. Still don't know what was the original cause of failure. Boss is going to see if his son want's us to pull the engine to see if it's worth a couple of rebuilt heads.

Edit: Question not really clear. Do the 05 and up engines have the spacers on the rocker arm carrier bolts?

Matt Saunoras · November 2, 2015

Yes the rocker pedestals should have bolt spacers BUT if the head bolt is in place there is no reason that pedestal should ever move.

Any slack in the valve train should automatically be taken up by the hydraulic lifter. I wonder if there is an issue with it. With the pushrod out take a peak down at the top of the lifter and make sure the square spring clip is there

lmorris · November 2, 2015

The top of the lifter looks good and it is not "mushy". This thing has always had the tell tale pop of a bad valve, but they never did anything about it because it ran great. We did check the valve lift and it is ok. With #2 intake valves no longer opening the pop is gone. Boss priced out a couple of heads and full set of push rods. Will check cam lobe again when heads are off.

forddieseldoctor · November 7, 2015

This thing has always had the tell tale pop of a bad valve, but they never did anything about it because it ran great.

Are you talking about that hollow knocking noise that some of the 6.0's have at idle?

lmorris · November 11, 2015

This thing has always had the tell tale pop of a bad valve, but they never did anything about it because it ran great.
Are you talking about that hollow knocking noise that some of the 6.0's have at idle?

No, it was definitely popping through the intake, you could hear it at the air filter horn. We even had to side by side and it was noticeably different. My guess is a bad valve seat seal more than anything. I will have a better look at them when I get the heads off. That will have to wait till I get back from my holiday in Disneyworld though.